The Peter Lyon Papers concern the professional development of a mid-20th century muckraker between 1939 and 1969. The documentation includes biographical material, general correspondence, 1942-1969, materials on his articles and books, book reviews, radio scripts, and photographs.

There is one folder of biographical material concerning a wealth of personal and medical information.

The general correspondence covers many facets of Peter Lyon's career and consists of business, financial, fan, and family letters. Many of the outgoing letters, which contain long commentaries on Lyon's activities, were in poor condition upon arrival at the Historical Society and have been replaced by photocopies. The letters mainly concern his activities as a writer, however Lyon often made comments on his financial status and political beliefs. Other correspondence on specific articles, books, and radio programs is filed with the material it relates to.

The articles section includes correspondence, research notes, outlines, drafts, and tear sheets of Lyon's articles. These articles, dating mainly from 1949 to 1969, cover a wide topic range including historical essays on the West, urban problems, and railroads.

The section on books contains documentation for four of his published books as well as unpublished manuscripts and book proposals. There is only a draft copy for Alcoholism, Its Scope, Cause and Treatment. Material on his other published books is more extensive and includes correspondence, research material, drafts, galleys, reviews, and advertising. The research file for To Hell in a Day Coach is unusually complete.

Lyon's major book is Success Story: The Life and Times of S. S. McClure (1963). The correspondence contains fan mail, business letters with the publisher, information on McClure and his era from family members, and critical reactions from prominent historians like Eric F. Goldman. The research material contains notes, clippings and articles by Lyon, photocopies of manuscript drafts by Lincoln Steffens, and an original manuscript by publisher Curtis Brady. The McClure family allowed Lyon to use McClure's correspondence with Stephen Crane, Ida Tarbell, Mark Twain, and others. There is also other correspondence about McClure written by immediate family members. Ida Tarbell, and other individuals who knew him well. This collection contains only photocopies of the McClure letters; the originals were added to the S. S. McClure Papers at the Lilly Library, the University of Indiana, Bloomington.

Unpublished manuscripts and book proposals contain research materials and manuscripts for “Isaac Singer,” “Scoundrels, Imposters, and Healers,” and one unidentified manuscript.

One folder contains book reviews written by Lyon during the 1960s.

The radio section contains correspondence and scripts for series and special programs. The correspondence includes CBS radio agreements and letters concerning Lyon's scripts and financial arrangements. The scripts for series cover the period 1939 to 1951 and include such series as Cavalcade of America, 1939-1942, The Eternal Light, 1948-1951, and Labor for Victory, 1942-1944. The scripts for specials include Bretton Woods, 1945, and The Hollywood Picture, 1948, which has six drafts in chronological order, correspondence, and clippings. One folder contains miscellaneous fragmentary scripts for specials.

The remainder of the collection is made up of photographs of Peter Lyon and one picture of Mrs. Franklin D. Roosevelt.